Speed changing mechanism



Oct. 4, 1938. J. E. TORBERT. JR 2,132,088-

SPEED CHANGING MECHANISM Original Filed March 4, 1936 2 Sheets-Sheet l Ax/ I Swumm 1 2 Join E. Ybrfiefigeff.

Oct. 4, 1938. J. E. TORBERT, JR 2,132,088

SPEED CHANGING MECHANISM Original Filed March 4, 1936 2 Sheets-Sheet 2 F'wzZ JoAn Z. Tbrberifi]:

Patented Oct. 4, 1938 UNITED STATES SPEED CHANGING MECHANISM John E. Torbert, Jr., National City, Calif.

Original application March 4, 1936, Serial No.

67,146. Divided and this application September 10, 1936, Serial No. 100,183

3 Claims.

This invention relates to an improved speed changing mechanism particularly adapted for use with electric drill tools and the like and is a division of my co-pending application for a patent for a Drill, Serial No. 67,146, filed March l, 1936;

now Patent No. 2,106,937.

One object of my invention is to provide a speed changing mechanism which will permit the drill chuck of an electric drill or the like to be driven at either high or low speed, depending upon the work to be drilled, so that the necessity of the operator removing his hand from the handle of the device to effect speed changes at remote points will be obviated.

Another object'of the invention is to provide a device of this character which will be simple in construction, light in weight, and positive in action.

A further object of the invention is to provide :a speed changing mechanism wherein provision is made for turning off or on the motor employed for driving the drive shaft of said mechanism.

A further object of the invention is to provide a speed changing mechanism wherein a removable auxiliary handle is employed for permitting both hands of the operator to be used when it is desired'to exert great pressure upon the work being drilled.

Other and incidental objects of the'invention will render themselves apparent as the description' proceeds.

'My improved speed changing mechanism is illustrated in the accompanying drawings, wherein:

Figure 1 is a vertical sectional view of the structure;

Figure 2 is a vertical sectional view of the mechanism, taken along the line 22 of Figure 1,

looking in the direction indicated by the arrows.

various views, the numeral indicates in general a handle of my improved speed changing mechanism which carries at itsupper end a tubular head 2 projecting upwardly and rearwardly therefrom. The handle defines a housing for the gearing employed, as will be seen hereinafter. The rear end of the tubular head is closed by a threaded plug 3. The bore of the head 2 has its lower portion provided with an opening intermediate its length for permitting the establishment of communicationwith the handle which is hollow throughout its interior, and in this bore there is fitted a tubular shaft housing 4, held in place and prevented from rotating by set screws 5. Bearings 6 and l are rotatably mounted in the shaft housing to support a shaft 8 which terminates at its forward end in a head or -nipple 9 formed with a squared shank i0 adapted to correspond to a socket formed in a like shank on a drill chuck which is adapted to be screwed on the projecting threaded end portion H of the shaft housing 4. Lock nuts l2, which are adapted to lock the housing 4 in place, are carried by the threaded portion A beveled gear I 3 is fixed to the shaft 8 forwardly of the bearing l and is adapted to mesh with a companion beveled gear I4 which is carried by a shaft l5 rotatably mounted in the handle I by hearing bars I6 and llwhich extend transversely in the handle and Y are secured in place by screws l8. An' opening I9 is formed in thetubular shaft housing l in order that the beveled gears |3 and I4 may have ready meshing engagement with each other. By re; fern'ng to Figure 2 of the drawings, it will be seen that the shaft l5, which is better known as a countershaft, is loosely received in clutch sleeves 28 and 2| which are journaled through the bearing bars I6 and M, respectively. Disposed on the countershaft I5 and between the clutch sleeves 2E] and 2| is a clutch sleeve 22 which is-slidable longitudinally on the countershaft but is held against rotation thereon by a key 23. By shifting the clutch sleeve 22 longitudinally upon the countershaft, it will be understood that selective engagement of said'clutch sleeve 22'with either of the clutch sleeves 2B or 2| may be had and,

furthermore, by disposing the clutch sleeve 22,

midway between the clutch sleeves and 2|, rotation of the countershait may be brought to a stop. Actuation of the shiftable clutch sleeve 22 is accomplished through the medium of a boss 24 having arms 25 which are engaged in a circumferentially extending groove 26 formed in said shiftable clutch sleeve. The boss 24 projects from a flat plate 21 which bears against the inner face of a detachable closure plate 28 carried by the handle I. In order to hold the plate 21 against the closure plate 28 I have provided resilient strips 29 which are carried by blocks 38, which blocks project inwardly from the closure plate 28.

As best seen in Figure 3 of the drawings, teeth 3| project from the resilient strips 29 to engage in grooves 32 formed in the plate 21 and which are adapted to guide sliding movement of said plate. Attention is directed to the fact that when the teeth 3| are out of the grooves 32, as shown in Figure 3, the resilient strips 29 will apply pressure to the plate 21 and hold it firmly against the inner face of the closure plate 28 to prevent the escape of lubricant .with which, the hollowhandle is filled, through an opening 33 formed in said closure plate substantially medially thereof.

The opening 33 extends longitudinally of the 0105-.

ure plate and has lateral recesses or extensions 34 and 35, at its opposite ends, which extensions serve as seats for the shank 36 of the actuating button 31. The button 31 terminates in a stem or shank which is tightly screwed. into a socket formed in the plate and the shank of the boss 24 and, referring to Figure 4 of the drawings, it will be readily seen that by grasping the button 31 the shank 36 thereof may be shifted longitudinally of the opening 33 in either direction for shifting the clutch sleeve 22 from a neutral position, as shown .in Figures 1 and 2, to an opera-..

- reaches either end' of the opening 33, it will be moved laterally into either the recess 34 or the recess 35, according to the direction in which it has-been shifted, and the shiftable clutch sleeve will thus be. firmly held in a set position and rotary motion will be imparted to the shaft l5 either by the clutch sleeve 26 or the clutch sleeve 2|. The clutch sleeve ZOis formed'with a circumferentially extending spur gear 38 which meshes with a companion gear 39 carried by a shaft 40. As best seen in Figure 1 of the drawings, the shaft 40 isjournaled through the hearing bars l6 and I1 and has its rear end terminating in a socket 4| adapted to receive the shank 42 of a flexible shaft 43 when the cable 44 of said flexible shaft is screwed into a threaded socket 45 which is formed in the thickened lower endwall 46 of the hollow handle I. It will be understood that the shaft '40 rotates at the same rate of speed as the flexible shaft 43 and, as the clutch 2|] turns at thesame rate of speed as the gear 39, rotary motion at a high speed will be transmitted to the shaft I5 and thus to the shaft 8 when the shiftable clutch sleeve is in.

engagement with the clutch sleeve 23.

The countershaft l5 will be rotated at a reduced speedwhen the clutch sleeve 22 is in engagement with the clutch sleeve 2 I, as the clutch sleeve 2| carries, at its rear end, a beveled pinion 41 which meshes with a companion beveled pinion 43 carrie'd'by a Worm gear 49, the Worm gear being rotatably mounted and having the stem 55 thereof journaled in a block 5| which projects rearwardly or downwardly from the bearing bar l1 integral therewith. The marginal teeth of the worm gear 49 are disposed in meshing engagement with'threads of the worm 52 which is carried on and fixed to rotate with the shaft 40. It will thus. be seen that a drill may be operated either at high speed or at low speed, according to the type of materialin which an opening is to be drilled. It will further be under 1 stood that the actuating button 31 may be quickly shifted for controlling the speed or completely stopping rotation without the necessity of the operator removing his hand from the handle I of the tool. A terminal socket 53, to receive the prongs of an electric connecting plug 54, is

trigger guard 63 which trigger guardprojects forwardly from the handle I under the head 2. In the guard there is mounted a trigger 6| which is pivoted at its upper end, as shown at 62, and carries a lug 63 for shifting the arm 64 inwardly against the action of a spring for bridging the contacts 51 when pressure is applied to the trigger.

It will thus be seen that an operator, grasping the handle i, may easily pass a finger through the trigger guard and, by applying pressure to the trigger, close a circuit for setting in operation the motor connected to a source of power and to the contacts 51. When the trigger is released, the circuit will be broken by reason of the fact that the spring 65 will urge the arm 64 outwardly out of engagement with the contacts 51.

In some instances, it will be desirable to hold the drill in both hands so that it may be held very easily and so that more pressure may be applied if necessary. Therefore, in order to accom plish this, I provide an auxiliary handle indicated in general by the numeral 66 and which includes a relatively short metalbar 61 having a threaded end portion 68 adapted to be screwed into the socket 59 of a yoke 19. The arms 1| and 12 of the yoke diverge from the socket 69 so that they will have fiat contacting engagement with-the beveled side faces of a saddle'13 which is formed integral with the head 2 by thickeningthe inter-v mediate portion of said head. As best seen in Figure 2 of the drawings, this saddle projects from opposite sides of the headto form shoulders and the free or lower end portions of the-arms 1| and 12 are bent to form hooks 14 which engage under the shoulders ofthe' saddle. It will also be seen in Figure 2,.that when the handleGB is screwed into the socket 69,'the innerend of said handle will engage the upper face'of the: saddle and Will exert a pull upon the arms 1| and 12 of the yoke and cause their hooked ends tobe' moved into tight binding engagement with the shoulders of the saddle. The handle will thus be firmly held in place on the saddle andthe operator may grasp the handle 66 with onehand and the handle with the other hand so thatthe entire mechanism may be held very easily when in use.

When the auxiliary handle is not needed, it' is only necessary to rotate the metal bar 61 thereof in a direction to loosen it, so that the'hooked ends 1 I 14 will be freed from binding engagementwiththe saddle. The yoke may be shifted longitudinally of the saddle out of engagement therewith so that the auxiliary handle may until again needed.

It is thought that a reading description will disclose that I have provided a be laid aside of the foregoing simple yet highly efficient speed changing mechand having a bore, a tubular shaft housing in the bore, a shaft in the housing, a countershaft in' the handle, means rotatably mounting the countershaft in said handle, clutchsleeves rotatably" mounted on said countershaft, a movable clutch sleeve slidable on the countershaft and fixed to rotate therewith, means carried by the handle for shifting the movable clutch sleeve, a drive shaft carried by the 'handle, a flexible shaft operatively connected with the drive shaft, a worm carried by the drive shaft near its lower end, a gear carried by the shaft at its upper end, a gear carried by one of the clutch sleeves and adapted to engage said first mentioned gear, means rotatably connecting the worm with the other of said clutch sleeves, and means for imparting rotation from the countershaft to the first mentioned shaft, said movable clutch sleeve being adapted for connecting the countershaft to one of said clutch sleeves for relatively slow rotative movement or to the other of said clutch sleeves for relatively fast rotative movement.

2. In a speed changing mechanism, a handle defining a housing, a head carried thereby and having a saddle, an auxiliary handle associated with the head and having a relatively short bar terminating in a threaded end portion, and a yoke having arms straddling the saddle and terminating in hooks adapted to engage the saddle, said short bar being adapted to be screwed into the yoke for tightening the hooks against the saddle and retaining the auxiliary handle on the head and said bar being rotatable for releasing the auxiliary handle from the head.

3. In a speed changing mechanism, a handle defining a housing, a head formed thereon and having a bore, a shaft housing carried by the bore, a shaft rotatable in the bore, bearings journaling the shaft in the bore, a countershaft carried by the handle, beveled gears for transmitting rotation from the countershaft to said first mentioned shaft, clutch sleeves rotatably for transmitting low speed rotation to the other of said clutch sleeves, and bearing bars carried within the handle for mounting said shafts and sleeves, said movable clutch sleeve in one position being adapted to transmit relatively slow rotative movement to the first mentioned shaft and in another position to transmit relatively high speed rotative movement to said first mentioned shaft and said movable clutch sleeve being shiftable to an intermediate position for retaining the countershaft in a non-rotating position.

JOHN E. TORBERT, JR. 

